Friction-sprocket.



' of teeth.

Enron.

EMIL F. HAFELFINGER, OF WEEHAWKEN, NEW JERSEY.

FRICTION-SPROGKET.

T 0 (ill whom it may concern:

Be it known that 1, Earn. F. HAFELFINGER, a citizen of the United Statesof America, residing at Weehawken, in the county of Hudson and State ofNew Jersey, have invented a new and useful Friction-Sprocket for Motor-Bicycles, &c.; and I do hereby declare the following to be a full,clear, and exact description of the same.

The present invention especially relates to improvements in sprocketsfor motor bicycles, automobiles or other self-propelled vehicles, andthe primary object thereof is to provide a sprocket having its toothedrim adapted to slip relatively to its web or some other part of thedriving connections.

It is well-known that when gearing is employed to transmit motion from arotary shaft to an axle (for instance), a great strain is thrown uponthe gearing when the bicycle or other vehicle is started by theinfluence of the motor, and there is likelihood of breaking theconnections. Thus, for instance, when a motor bicycle is provided with asprocket driven by a shaft connected with an explosion-engine, and witha chain from said sprocket to another sprocket upon the rear wheel ofthe bicycle, it frequently results, upon starting the motor, that thechain is snapped or either of said sprockets is stripped In order toprevent such accidents, I provide a sprocket having a toothed rimadapted to have a restrained movement independently of the rotation ofthe driving shaft, and for this purpose I provide the sprocket withfriction material between the rim and the web and with means for holdingthe several parts in constant friction relation.

The accompanying drawing shows one form of my new sprocket connectedwith the pedal shaft of a motor-bicycle, the sprocket being shown insection.

1 indicates a sleeve comprising the tube 4 usually at the junction ofthe brace or frame member or members with the bottom front brace 12 of abicycle (see especially United States Patent No. 682682) granted to me.

2 indicates a rotary shaft, such as a starting shaft, as, for instance,a pedal-shaft, to the opposite ends of which pedal-cranks 95 may besecured in any of the usual ways. The shaft 2 rotatably fits within asleeve 3, which in turn rotatably fits within the sleeve 1. Antifrictionbearings, are interposed between the shaft-2 and the sleeve 3, andbetween Specification of Letters Patent.

Application filed August 29, 1906.

the washer 24.

Patented May 5, 1908.

Serial No. 332,435.

the sleeve 3 and 1, and in the drawings, I have shown balls 6 and 16 forsuch purposes.

At one side of the bicycle frame, I have provided a lock block 7,surrounding and brazed to the shaft 2; such block 7 is externallythreaded, and such exterior threads engage with threads 9 upon the innerwalls of one ring or member 8 of a ball or roller clutch, the othermember (10) of which is also shown as a ring or washer havingthreadsupon its inner wall in engagement with threads upon the end of sleeve 3.The ballclutch is shown as provided with a dust-cap 12, secured bythreads 11 to the clutch-member 10. Rollers 13 are located between'theparts 8 and 10, and either of such parts may be suitably formed topermit the shaft 2 to drive the sleeve 3 only when the shaft moves inthe forward direction, and which also permits the sleeve 3 to be movedforwardly by a motor, without contributing movement to the shaft. A formof ball-clutch useful for such purpose is shown in my aforesaid Patent682682.

In addition to threads 11, already mentioned, the sleeve 3 is alsoprovided with threads 14, and the last-named threads engage withcorresponding threads in the interior of the hub of a sprocket, whoseWeb is indicated at 17. Such web is provided With an annular flange orrim 18, and the latter is shown as provided with a tapered or conicalface or periphery 19.

A correspondingly-tapered ring 20 of friction material, such as frictionmetal, surrounds the conical periphery 19 and fits between said face anda conical recess or socket 21 of a sprocket rim surrounding the frictionmaterial and provided with radial teeth 22. The friction material 20 maybe secured to either the flange 18 or to the sprocket, or be free ofboth said parts.

A washer or ring-like plate 24 is disposed at one side of the sprocket,and is held in position to be adjustably clamped by the bolts 25, thethreaded shanks whereof engage openings in the web 17 of the sprocket,and the heads of which engage the outer face of The inner face of washer241 is provided with a washer or plate 23 of friction material (such asa friction metal), and the illustrated construction is such that thetightening of washer 24 results in pushing the material 23 against thesprocket-rim 21 and against the conical ring of friction material 20,thus clamping the ring against the conical face or periphery 19 of theweb, and holding the rim in clamped relation with the eX- terior of thering of frictional material. It is obvious that any desired adjustmentand compensation for wear may be assured by tightening any one or moreof the bolts 25. It is also obvious that the arrangement of parts shownis one which holds the parts of the sprocket firmly and constantlyengaged in frictional relation, permitting however some degree ofindependent movement of the toothed rim.

The washer 24 is provided with an inwardly-extending edge flange 26which fits within a recess in the web 17 and concentric to the aXis ofthe sprocket.

Any suitable form of chain may lead from the sprocket teeth 22 andengage directly or indirectly with the rear bicycle-wheel or otherpropelling wheel.

In operation, when. starting the motor, the shaft 2 will first be movedforward, by pedal- .mg or otherwise, and the ball clutch 810 will engageand rotate the sprocket and the sleeve 3, the latter operating the fueland airsupply. valves and the ignition apparatus. As soon as the chargeis ignited, the sudden starting strain therefrom will be thrown upon thesprocket. The usual jerk thereby imparted to the drive chain andsprocket teeth will not, however, be present in my structure, since,owing to the friction material between the periphery 19 and the toothedrim, there will be enough slipping between the web and the rim, eventhough tightly held together, to enable the rotation of the sleeve 3 tobe somewhat gradually imparted, with a minimum of jerking strains, tothe rim and to the chain. It will be obvious, of course, that the rimwill also slip in its engagement with the washer 23 of frictionmaterial.

When the bicycle or other vehicle has attained sufficient headway, therewill be no further slipping of the sprocket rim, and the sleeve 3,sprocket and chain will operate without any unusual give between theparts.

What I claim is:

1. A sprocket having a web provided with a conical periphery, a toothedrim having a conical inner wall, and surrounding said web, frictionmaterial betweenthe conical faces of said parts, and means forconstantly clamping both parts and the friction member in engagement.

2. A sprocket having a web and a toothed rim separate therefrom,friction material between said hub and said rim and slidably engagingwith one of said parts, and means for pulling said two parts in oppositedirections and for pushing the friction material between said parts.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses.

EMIL F. HAFELFINGER.

Witnesses MAX MARTIN, FREDERICK BERENBROIGK.

